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{
"metadata": {
"name": "",
"signature": "sha256:cc924f0db45ef8f074cc8f1d8a1ee198ea5115e6305e3da74ea78f614afb5f88"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Chapter5- Physical Similarity and Dimensional Analysis"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex3-pg184"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate The total resistance of the prototype\n",
"u_p=10.; ## m/s\n",
"scale=1/25.; ## l_m/l_p\n",
"L=125.; ## m\n",
"meu=1.235*10**(-6); ## m**2/s\n",
"meu_p=1.188*10**(-6); ## m**2/s\n",
"rho_p=1025.; ## kg/m**3\n",
"rho_m=1000.; ## kg/m**3\n",
"A=3500.; ## wetted surface in m**2\n",
"\n",
"u_m=u_p*math.sqrt(scale);\n",
"\n",
"d=L*scale;\n",
"Re=d*u_m/meu; ## Reynolds no.\n",
"C_F=0.075/(math.log10(Re)-2)**2; ## Skin friction coefficient\n",
"\n",
"res_skin=rho_m/2*u_m**2*(A*scale**2)*C_F;\n",
"\n",
"res_tot=54.2; ## N\n",
"\n",
"F_resid_m=res_tot-res_skin;\n",
"\n",
"F_resid_p=F_resid_m*rho_p/rho_m/scale**3;\n",
"\n",
"Re_p=u_p*L/meu_p;\n",
"\n",
"C_F_p=0.075/(math.log10(Re_p)-2)**2+0.0004;\n",
"C_F_pnew=1.45*C_F_p;\n",
"\n",
"res_friction=rho_p/2*u_p**2*A*C_F_pnew;\n",
"\n",
"Resistance=F_resid_p+res_friction;\n",
"print'%s %.1f %s'%(\"The total resistance of the prototype\",Resistance,\"N\")\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The total resistance of the prototype 809273.4 N\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex4-pg 184"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate Maximum speed of the redesigned torpedo\n",
"\n",
"A=0.88; ## ratio of A2 and A1\n",
"C_D=0.85; ## ratio of C_D2 to C_D1\n",
"P=1.20; ## ratio of P2 to P1\n",
"V1=11.; ## m/s\n",
"\n",
"V2=V1*(P/A/C_D)**(1/3.);\n",
"print'%s %.2f %s'%(\"Maximum speed of the redesigned torpedo =\",V2,\"m/s\")"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Maximum speed of the redesigned torpedo = 12.88 m/s\n"
]
}
],
"prompt_number": 2
}
],
"metadata": {}
}
]
}
|
